Search for files with more than one term (grep, awk?)

Question

I am using a command like this to find files with the word 'term' in them:

grep -l term *

But I now want to be able to find files which have two different words in them (let's call them termA and termB) - not necessarily on the same line. I want to find files with both terms in, not just files that have either term.

Now I could write a cumbersome bash script for this, but does grep, egrep, awk, sed or anything else have a tool that can help me?

Thanks in advance.

Answer 1

If your files contain no null bytes

In this case, you can use grep alone:

grep -Plz "termA.*termB|termB.*termA" *

How it works:

• The Perl Compatible Regular Expressions termA.*termB and termB.*termA search for strings which have both terms in it.

• The combined PCRE termA.*termB|termB.*termA matches all strings containing both terms.

• Finally, the -z switch makes data lines end in null bytes instead of newlines.

By the way, there's no need to use -P. If you prefer to continue using POSIX Basic Regular Expressions, the syntax is similar:

grep -lz "termA.*termB\|termB.*termA" *

If your files contain null bytes

In this case, you'll need auxiliary tools:

(grep -l termA * ; grep -l termB *) | sort | uniq -d

How it works:

• grep -l termA * ; grep -l termB * displays all files containing either of the terms. Files that contain both terms will be displayed twice.

• sort sorts the output.

• uniq -d only displays duplicate lines (required lines to be sorted).

Answer 2

You can use either the -e or -f options to search for multiple expressions (from man grep):

    -e PATTERN, --regexp=PATTERN
          Use  PATTERN  as  the  pattern.   This  can  be  used to specify
          multiple search patterns, or to protect a pattern beginning with
          a hyphen (-).  (-e is specified by POSIX.)

   -f FILE, --file=FILE
          Obtain  patterns  from  FILE,  one  per  line.   The  empty file
          contains zero patterns, and therefore matches nothing.   (-f  is
          specified by POSIX.)

So you would use this as:

$ grep -e termA -e termB *

Answer 3

grep supports regular expressions as far as I know. I use the following syntax to search multiple terms:

    grep 'termA\|termB' /i/am/a/path

you do need to use the escape character '\' before each '|' but with that I bvelieve you can use as many search strings as you want